Manufacture of staple fiber yarns and tows



Dec-9,1941 V J. A. TRUITT 2,432,355 T MANUFACTURE OF STAPLE FIBER-YARNS AND TOWS Filed June 7, 1945 v mmvrda.

fiwam Patented D ecr 9, 1947 MANUFACTURE or s AND mm FIBER YARNS 'row i Joseph A. Truitt, West Chester, Pa., assignor to i American Viscose Corporation, Wilmington, ,Del., a corporation of Delaware 1 Application June 7, 1945, Seriallflo. 508,005

- This invention relates'to a. procedure and apparatus for converting continuous filament bundles, such as yarns or tows, into staple fiber bundles without the loss of continuity of the bundle. i i

Heretofore, it has been the common practice to subject continuous filament bundles without twist or having an extremely low twist, to adrafting action by which the filamentsare' stretched beyond the limit of their extensibilities to effect breakage thereofisuch as between two or more spaced pairs of drafting rolls or equivalent stretching devices. This procedure has the disadvantage of requiring a large filament bundle, such as 10,000 to 200,000 denier, in order to assure that the entire bundle is not interrupted at intervals and to avoid the tendency of broken ends to fly out of the general bundle. 1

In accordance with the present invention, the position of breaking of the fibres is controlled in an improved fashion, so that the loss of ends by A complete interruption of the bundle is prevented and the tendency of the broken terminal portions of the filaments to fiy is reduced to a negligible quantity. In general, the objects of the invention are accomplished by first twisting the bundle a substantialamount, such as 3 to 25 turns per inch, and then introducing the twisted bundle .into the drafting system while subjecting the bundle as it proceeds between the pairs of drafting rolls to a false twistingactionin a direction opposite to the twist in the bundle as it enters the system. The false twisting requires the engagement of the bundle at adeflnite position of its path between the pairs of drafting rolls and reduces the twist adjacent the point of engagement to either a low twist or to no twist at all. The low twist may be either in the same or the opposite direction. to that originally in the bundle as it enters the system. Because of the rotation of the point of engagement of the bundle with 14 Claims. 01. 57-2) the bundle remains in integral assemblage. The twist of the bundle as it leaves the draftingsystem is less than the twist of the bundle as] it is fed thereto, depending inversely upon the drafting ratio, butt he initial twist of the continuous filament bundle may be ofsufficient magnitude so that it is unneoessaryto provide additional twisting to the staple fiber bundle issuing from the drafting system, or to take special precautions to assure unity or the staple fiber bundle as it proceeds toa twisting device following the drafting In some cases, it maybe desirable to add additional twist, but for many purposes, the final twist desired in the stable fiber bundle may be obtained merely by predetermining the twist in the continuous filament bundle as it is provided for delivery to the drafting system.

Thus, the false twisting system assures, staggered breaks at fairly definitely controlled dis- ,tances apart, prevention of lost ends flying from the staple fiber bundle between the drafting rolls,

and elimination of the necessity to imparttwist or to provide special means to prevent interruption of the staple fiber bundle as it is discharged from the system.

The invention is applicable to the treatment of bundles of filaments of any character,;such as artificial filaments of regeneratedcelluloseproduced from viscose, ultra-cellulose, cuprammonium cellulose; cellulose esters, such as cellulose acetate, cellulose propionate, cellulose acetate butyrate; cellulose ethers, such asethyl cellulose and benzyl cellulose; nylons, such as the polyamides; proteinous fibers such as those from casein; resin fibers such as the vinyl polymers,

e. g. poyl-vinyl chloride, polyvinylidene chloride, copolymers of vinyl chloride and vinyl acetate, co-

polymers of vinyl chloride and acrylonitrile, polyethylene; resins from polyacrylic derivatives, such as polyacrylonitrile; and the like. The invention the false twisting system, and because of the continuous longitudinal travel of the bundle through the twisting system, a point of weakness is established in the filaments which engage'the twisting system, because of the low or complete lack of- .ment with the twister system. Another importantefiect of the procedure is to immediately retwist the broken fiber bundle as it proceeds from the false twisting system, thereby assuring that is also applicable to continuous filaments such as silk or those Of extremely long length which may desirably be reduced in length, such as hemp jute and the like.

The invention may be performed upon the dry continuous filament bundle or the bundle may first be wetted. Similarly, the process may be performedat room temperatures or at higher temperatures, the latter being particularly adapted to thermoplastic filaments which can be weakened by the heat. Alternatively, the wetting or heating, either expedient being used to weaken the fibers, may be applied locally, such as at the point of engagement of the false twisting system with the continuously traveling bundle. By this expedient. those fibers which make the immediate contact with the wet or heated engaging surface are momentarily and separately weakened; whereas the others are relatively unaffected, being out of engagement with the wet or heated surface.

The invention is applicable to bundles of a wide range of sizes, from 100 denier up to 200,000 denier and has the advantage over the breaking systems using low twist or none at all that such low denier sizes as 100 to 1,000-or even 10,000 denier can satisfactorily be reduced directly to a staple fiber yarn without the necessity of additional drafting, such as would be required when, using a high denier tow. In addition, the present erated cellulose filaments, whereas acetone or I invention is adaptable to a wide range of draft ratios. Whereas the systems mentioned hereinabove require drafts of 2:1 to 7:1, lower drafts but slightly exceeding the break-extensibility of the fibers being used are satisfactory with the present invention though higher drafts, such as up to 40:1, may be used if desired.

Preferred embodiments of the invention are illustrated in the accompanying drawing, in which- Figure l is an elevation, partially in cross-section, of a preferred embodiment;

Figure 2 is a modification; and

Figure 3 is a further modification. 1

Referring to Figure l, a twisted continuous filament bundle 2 proceeds about a roll 3 and then around a roll 4 constituting the upper of the first pair of driven drafting rolls 4 and 5 between which the bundle is nipped. From the pair of rolls 4 and 5 the bundle proceeds through a false twisting device 6 comprising a rotatable tube 1 within a bearing 8 driven by a pulley 9 and a belt ID. The tube 1 may contain any form of trapping or filament-engaging device, such as the disc ll having an eccentric bore I2 securely fastened in the tube adjacent its discharge end. From the twister 6 the bundle proceedsthrough a pair of drafting rolls l3 and I4 driven at a higher speed than rolls 4 and 5, from which it is discharged in a twisted condition and as stated before, it may proceed to a twister to insert additional twist or merely to .a collecting device in which it may be wound without further twist being imparted.

The surface of the bore l2 in the disc II which engages the filaments in the bundle 2 controls the position of breaking actionand the length of staple fiber obtained in the final product can be generally predetermined by suitably selecting the draft ratio and distance between the engaging surface of bore l2 and the nip of the rolls l3 and I4.

The portion of the surface of bore 12 that engages the bundle may be somewhat roughened or sharpened to an edge extending transversely to the bundle, so that an abrasive or cutting effect may be exerted upon the filaments as they are engaged.

' In Figure 2 a modification is provided in which the disc Ila corresponding to the disk ll of Figure 1 has a central axial channel l5 which communicates with a radial channel I 6 opening into the bundle-engaging surface of the bore |2a and a nozzle I! which fluid, such as a liquid by a pump l8 projects into the passage l5, so that a liquid may be forced therein. By centrifugal force, the liquid will fiow outwardly through the radial passage and make contact with the filaments of the bundle bearing on the adjoining surface of the bore l2. The reservoir I 9 may contain any desired liquid such as cold or heated water, acetone, or other softening, solvent, or weakening liquids. Water 'is particularly useful in connection with regenmaybe supplied with aan acetone solution in water is adaptable particularly to cellulose esters and vinyl resins for which they have a softening or solvent effect. Heated air may also be thus applied to weaken the filaments, especially of the thermoplastic materials.

Figure 3 shows a modification in which the bundle 2 proceeds about a driven draw wheel or godet 20 and an associated wrap-displacing guide 2|; through a false twister 22 and then about a second draw wheel or godet -23 and its associated wrap-displacing guide 24, the draw wheel 23 being driven at a higher speed than godet 20 in tinuous filament bundle into a of; the filaments adjacent order to effect stretching beyond the extensibility at break. The false twister 22 in this instance comprises a tube 25 adapted to be driven by the pulley 26 and belt 21 or equivalent means such as herein. Two. yarn-engaging levers 28 are pivotally mounted at 29 upon the lower end of the tube 25 in the position shown. The yarn-engaging portion of the levers is curved as illustrated, and if desired may be roughened, but is preferably smooth. The levers may be weighted at 30 so that during rotation of the twister tube the pressure of the levers upon the yarn increases because of the tendency of the weights 30 to fly outwardly. If desired, a ,fiuid, such as heated air or a liquid as in the embodiments mentioned hereinabove, may be applied by means of the nozzle 3| to the bundle adjacent thetwister, such as just above it, as shown.

In the claims, the work extensibility" is intended to refer to the elongation at break.

While specific embodiments of the invention have beenshown and described, it is to be understood that these are merely illustrative, and that changes may be made without departing from the spirit and scope of: the invention as defined in the appended claims.

I claim: I

l. The process of converting a twisted continuous filament bundle into a staple fiber yarn comprising continuously forwarding the twisted bundle longitudinally while subjecting it to a stretch in excess of the extensibility of the individual filaments therein, and simultaneously reducing the twist of the bundle along an intermediate portlon thereof under the stretching tension by subjecting it to a false twisting operation. a

2. The process of converting a twisted con comprising continuously forwarding the twisted bundle longitudinally while subjecting it to a stretch in excess of the extensibility of the individual filaments therein, and simultaneously reducing the twist of the bundle along an intermediate portion thereof under the stretching tensionby subjecting it to a false twisting operation and weakening at least 'part of the filaments adjacent the positionof minimum twist.

- 3. The process of converting a twisted continuous filament bundle into a staple fiber yarn comprising continuously forwarding the twisted bundle longitudinally while subjecting it to a stretch in excess of the extensibility of the individual filaments therein, and simultaneously reducing the twist of the bundle along an intermediate portion thereof under the stretching tension by subjecting it to a false twisting operation and applying a weakening fiuid to parts the position of the minimum twist.

4. The process of converting -a-twisted' constaple fiber yarni of continuous filaments of a ation and applying a softening liquid toparts f of' the filaments adjacent the position of the minimum twist.

5.,The process of converting a twisted continuous filament bundle into a staple'fiber yarn comprising continuously forwarding the twisted bundle longitudinally while subjecting it to' a stretch in excess of the extensibility of the in-' dlvidual filaments therein, and simultaneously reducing the twist of the bundle along an intermediate portion thereof under the stretching tension by subjecting it to a false twisting operation and applying a heated gas to partsof the filaments adjacent the position of the minimum twist.

6. The process of converting a twisted bundle of continuous filaments of regenerated cellulose into a staple fiber yarn'comprising continuously forwarding the twisted bundle nongiruamany while subjecting it to a stretcjhihe'xkress. of the extensibility of the individualffilainents therein,

and simultaneously reducing v thetwistlof the -tinuous filament bundle to a staple fiber bundle bundle along an intermediate.portion thereof under the stretching tension;byfsubjectingit to a false twisting operation andfaipplyirig water to parts of the filaments adjacen the position of minimum twist. i

7. The process of converting at'w s'ted bundle of continuous filaments of, an organic derivative of cellulose into a staple fiber yarn comprising continuously forwarding the twisted bundle longitudinally while subjecting it to a stretch in excess of the extensibility of the individual filaments therein, and simultaneously reducing the twist of the bundle along. an intermediate portion thereof under the stretchingtension by sub-- jecting it to a false twisting operation and applying acetone to parts of the filaments; adjacent the position of minimum twist. j

8. The process of convertinga staple fiber yarn: comprising continuously forand simultaneously reducing the twist of? the twisted bundle. vinyl. res-in into a 50.

{driven drafting rolls. means for driving the uous ifiiament bundle to a staple fiber. bundle comprising two spaced pairs of driven drafting rolls, means for driving the second pair at suflicient speed in excess of that of the first to stretch the twisted bundle as it passes through the rolls in succession beyond the extensibility of the filaments therein, a rotatable tube through which the bundle passes between the pairs of rolls, means rotatable-with the tube for engaging the bundle as it passes therethrough, means forrotating the tube in a direction to reduce the twist in the bundle as it passes over the engaging means thereon, .and means for applying a fluid to the bundle-engaging means.

11. Apparatus for converting a twisted continuous filament bundle to a staple fiber bundle comprising two spaced pairs of driven drafting,

rolls, means for driving the second pair at suflig in the bundle as it passes over the engaging means thereon, and means for applying a fluid to the bundle-engaging means; 312. Apparatus for converting .a twisted concomprising two spaced pairs of driven drafting rolls, means for driving the second pair at sumfcient speed in excess of that of the first to stretch 'the twisted bundle 'as it passes through the rolls .in succession beyond the extensibility of the filaments therein,';a rotatable tube through which the bundle passes between the pairs of rolls, an eccentric borein the tube having a surface engaging thebundle, means for rotating the tube in a direction to reduce the twist in the bundle as it passes over the engaging surface, and means for wetting the engaging surface.

' rolls; and means a false twisting operation and applying'acetone to parts of, the filaments adjacent the position of minimum twist.

beyond the extensibillty'of thefilaments therein, a rotatable tube through which the bundle passes between the rolls, means rotatable with the tube for engaging the bundle as it passes therethrough,

, means for rotating the tube in a direction to reduce the twistin the bundle as it passes-over the engaging means thereon,and means for ap plying a fluid to the bundle-engaging means. a twisted contin 10. Apparatus for. converting a 13. Apparatus comprising two spaced pairs of driven drafting rolls, means for driving the second pair at a higher speed than that of the first patina-false for supplying the false twister withafiuid,

14. Apparatus comprising two spaced pairs of second pair at a higher speed than that of the first pair, a false'twister between the pairs of .l' r ui bundle along an intermediate portlonf'thereof" and a nozzle for applying a J 0 HQ d under the stretching tension by subjecting it to to the false twister. v

JOSEPH A. 'I'RUITT.

L f narjnan'ncns crrnn The" following references are of "record" in the r file of thislpatenti an s'rn'rns PATENTS v I Number Name v Date 2,097,340 Tracy NOV..2, 1,937 339,326 Schiei'ner Apr. :6, 1888 2,332,485,. Hanson .oct. 19,1943 2,049,905 ""Gminder Aug; 4, 1936 i FOREIGN PATENTS 7 Number Country Date 145,543 Germany Oct. 17, 1902 twister between the pairs of Great Britain Nov. 3. 1910 

